title: Photoinduced Charge Transfer from Titania to Surface Doping Site.
abstract: We evaluate a theoretical model in which Ru is substituting for Ti at the (100) surface of anatase TiO2. Charge transfer from the photo-excited TiO2substrate to the catalytic site triggers the photo-catalytic event (such as water oxidation or reduction half-reaction). We performab-initiocomputational modeling of the charge transfer dynamics on the interface of TiO2nanorod and catalytic site. A slab of TiO2represents a fragment of TiO2nanorod in the anatase phase. Titanium to ruthenium replacement is performed in a way to match the symmetry of TiO2substrate. One molecular layer of adsorbed water is taken into consideration to mimic the experimental conditions. It is found that these adsorbed water molecules saturate dangling surface bonds and drastically affect the electronic properties of systems investigated. The modeling is performed by reduced density matrix method in the basis of Kohn-Sham orbitals. A nano-catalyst modeled through replacement defect contributes energy levels near the bottom of the conduction band of TiO2nano-structure. An exciton in the nano-rod is dissipating due to interaction with lattice vibrations, treated through non-adiabatic coupling. The electron relaxes to conduction band edge and then to the Ru cite with faster rate than hole relaxes to the Ru cite. These results are of the importance for an optimal design of nano-materials for photo-catalytic water splitting and solar energy harvesting.
authors.affiliation: Gumilyov Eurasian National University Astana, Munaitpasov st. 5, 010008, Kazakhstan.
authors.forename: Talgat
authors.initials: T
authors.lastname: Inerbaev
authors.forename: James D
authors.initials: JD
authors.lastname: Hoefelmeyer
authors.forename: Dmitri S
authors.initials: DS
authors.lastname: Kilin
keywords: electron transfer; hot carrier relaxation; photocatalysis; ruthenium; transition metal doping; water oxidation